West Nile virus in horses

Previously, the West Nile virus was only found in Africa and East Asia, but since 2018 it has also been detected in northern Europe (Germany). And now, since September 2020, the first report in the Netherlands has occurred. The spread to Europe (and the rest of the world) may be due to the many international transports that currently take place, but also possibly due to global warming, which allows the virus to thrive in Europe as well. Read on this page what the West Nile virus is and how to recognize it in horses.

What is the West Nile virus?

The West Nile virus is a mosquito-borne virus that causes disease in humans and animals. The virus originally comes from Africa, but is now also present in Asia, North and South America, and parts of Europe. The West Nile virus is still relatively unknown in the Netherlands. Unfortunately, there is no therapy available for the virus, which is why recognizing the disease is crucial. The virus causes brain symptoms in horses, but can be easily prevented with an annual vaccination.

Migratory birds are the carriers of the virus and contribute to its spread. Through mosquitoes such as the tiger mosquito (but also the common mosquito), the virus is transmitted from bird to animal (or human). Fortunately, the virus is not contagious, it is only transmitted via the mosquito and not from horse to horse. It is likely the West Nile virus has now arrived in the Netherlands due to a warm summer with many mosquitoes.

Symptoms of West Nile virus in horses

Only 10% of infected horses show symptoms, fortunately 90% of the horses do not get sick. The incubation period of West Nile is 2-6 days and can occur in all horses of all ages. Diseased horses show flu-like symptoms (fever, lethargy, and reduced appetite). 30% of sick horses develop more severe symptoms, such as meningitis and neurological abnormalities. Muscle tremors, weak hindquarters, ataxia, and inability to stand up are the severe symptoms. These symptoms are similar to the neurological form of rhinopneumonia.

What to do if you suspect West Nile in your horse?

If you suspect West Nile, it is advisable to immediately have a blood test done to demonstrate the virus. Rapid detection is important for the treatment of the horse, but also to quickly assess how the virus is spreading in the Netherlands. West Nile is not only dangerous for horses, but also for humans.

Since there is no medication available for West Nile, you can only support an affected horse. Anti-inflammatories, painkillers, and diuretics can help make it easier for the horse. If there is no chance of recovery, it is best to choose euthanasia for the horse. But fortunately, only 10% of infected horses actually get sick and 30% of them have the severe symptoms.

How to prevent West Nile in your horse?

There are two things you can do to prevent your horse from getting West Nile. Firstly, annual vaccination, contact your veterinarian for this. Another preventive measure is to control mosquitoes. Prevent mosquitoes from breeding and horses from being bitten. Additionally, it is essential to have your horse's immune system in good condition. We recommend supplementing with minerals from the Bering Sea and doing a herbal detox in the spring and autumn.